Dyeing of nylon fibers by treating with nitrogenous condensation products



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Patented Jan. 4, 1949. r

DYEING F NYLON FIBERS BY TREATING WITH PRODUCTS NITROGENOUS CONDENSATIONJames Hutchlson MacGi-egor, Booking, Braintree,

England, assignor to Courtaulds Limited, London, England, a Britishcompany N 0 Drawing.

Application October 12, 1944, Se-

rial No. 558,469. In Great Britain November Claims. 1

This invention relates to the dyeing of nylon fibres with direct cottondyestuffs in an acid dyebath.

In British Specification No. 547,844. Courtaulds Limited, C. M.Whittaker and C. C. Wilcock have described a process for dyeing nylonwith direct cotton dyestuffs in an acid dyebath by carrying out thedyeing in the presence of an organic compound which increases theaffinity of the nylon for the dyestuffs. The list of organic compoundsin the specification includes cyanamide, guanidine, arylguanidines,dicyandiamide, dicyandiamidine and melamine.

I have now found that nylon fibres containing a water-insolublecondensation product of formaldehyde and cyanamide or a derivativethereof can be dyed with a direct cotton dyestuif from an acid dyebathwith a considerably enhanced rate of absorption. The water-insolublecondensation product may be incorporated in the nylon fibres by treatingthe said fibres with an aqueous solution containing formaldehyde andcyanarnide or a derivative thereof, either as such or in the form of awater-soluble precondensate, and subsequently heating to convert thewatersoluble condensation product into the insoluble form.

Cyanamide derivatives which may be used in the present invention aredicyandiamide, melamine, guanidine, biguanide and dicyandiamidine oralkyl, hydroxyalkyl or aryl substitution products of guanidine,biguanide and dicyandiamidine. Salts of any of these compounds may beused in preparing the impregnating solution.

When carrying out the present invention, I prefer to employ a paddingprocess and in this case to use a paddin liquor containing in each litrenot more than about grams of the cyanamide formaldehyde compound. If amore concentrated solution is used in the padding process, there is atendency during the subsequent dyeing process for precipitation of acomplex compound of the dyestufi and the cyanamide-formaldehydecondensate to take place, with the consequent production of weak andunlevel dyeings.

The process of the present invention is of particular value when it isdesired to use direct cotton dyestuffs, such as Chlorazol Fast Pink BKS(Colour Index No. 353 and Chlorazol Black BHS (Colour Index No. 401),which are absorbed very slowly by untreated nylon fibres. The Washfastness of the dyeings obtained b the process of the present inventionis extremely good and this result is obtained without impairment of all2 Y the light fastness. The nylon fibres, particularly in the form offabric, treated according to the present invention lose more or less oftheir characteristic soapy handle.

The following examples illustrate the nature of the present inventionwithout the invention being limited to these examples.

Example 1 A length of an all nylon fabric is padded through an aqueoussolution containing 10 grams of diphenylguanidine (dissolved in 10 cubiccentimetres of per cent acetic acid) and 50 cubic centimetres of 40 percent formaldehyde in each litre of solution, at ordinary roomtemperature. squeezed evenly, so that the fabric retains approximately70 per cent of its own weight of padding solution, dried at under 100cen-tigrade and finally heated at 140 centigrade for 10 minutes. 1kilogram of the so-treated nylon fabric is then entered at a temperatureof centigrade into 50 litres of a dyebath containing 2 per cent ofChlorazol Fast Pink BKS and 7.5 per cent of 80 per cent acetic acidcalculated on the weight of nylon, and dyeing continued at thistemperature for one hour. A full shade of pink, which is very fast toWashing, is obtained, while the dyebath is almost exhausted. A piece ofuntreated fabric gives a much paler shade of pink when dyed undersimilar conditions. Furthermore, the treated fabric possesses a lesssoapy handle than the untreated fabric.

Example 2 A length of an all nylon fabric is padded through an aqueoussolution containing 15 grams of dicyandiamide and 150 cubic centimetresof 40 per cent formaldehyde in each litre of solution at ordinarytemperature, squeezed evenly so that the fabric retains approximately'70 per cent of its own weight of padding solution, dried at undercentigrade and finally heated at l centigrade for 10 minutes. 1 kilogramof the .so-treated fabric is then entered at a temper- A length of anall nylon fabric is padded through an aqueous solution, containing 10grams of guanidine adipate and 150 cubic centimetres of 40 per centformaldehyde in eachlitre of solution, at ordinary tcmperatureysqueezedevenly so that it retains approximately 70 per cent of its own weight ofpadding solution, dried at under 100 Centigrade and finally heated at140 centigrade for minutes. ed fabric is then entered at a temperatureof 90 centigrade into 50 litres of a dyebath containing 1 per cent ofChlorazol Black BHS and 7.5 per cent of 80 per cent acetic acid,calculated on the weight of nylon and dyeing continued at thistemperature for one hour. A full shade is obtained and the dyebath iswell exhausted. The fastness to washing of the dyeing is extremely good.Untreated nylon dyed under similar conditions to those just described isdyed a very pale shade.

" Example 4 43 denier/17 filament scoured bright nylon yarn is paddedthrough an aqueous solution containing 20 grams of monoethanol biguanideneutral sulphate and 150 cubic centimenters of 40 per cent formaldehydein each litre of solution, at ordinary room temperature, squeezed evenlysothat yard retains approximately 70 per cent of its own weight ofpadding solution, dried at under 100 centigrade and finally heated at140 centigrade for 10 minutes. 1 kilogram of the so-treated yarn is thenentered at a temperature of 90 centigrade into 50 litres of a dyebathcontaining 1 percent of Chlorazol Fast Pink BKS and 7.5 per cent of 80per cent acetic acid, calculated on the weight of nylon, and dyeingcontinued at this temperature for one hour. A full shade of pink isobtained and the dyebath is well exhausted. The fastness to washing ofthe dyeing is extremely good.

What I claim is:

1. A process for dyeing nylon fibres at an enhanced rate of absorptionwith direct cotton dyestuffs having little afilnity for nylon whichcomprises incorporating in the nylon fibres a water-insolublecondensation product of formaldehyde and a member of the groupconsisting of cyanamide, dicyandiamidemelamine, guanidine, biguanide,dicyandiamidine, alkyl, hydroxyalkyl, and aryl substituents ofguanidine, biguanide and dicyandiamidine and dyeing the fibres with thedirect cotton dyestuff from an acid dyebath.

2. A process for dyeing nylon fibres at an enhanced rate of absorptionwith direct cotton dyestufis having little aflinity for nylon whichcomprises treating the nylon fibres with an aqueous solution containingformaldehyde and a member of the group consisting of cyanamide, dicyan-1 kilogram of the so-treat-- dlamide, melamine, guanidlne, biguanide,dlcyandiamidine, alkyl, hydroxyalkyl and aryl substituents of guanldine,biguanide, and dicyandiamidine, converting the formaldehyde and memberof the group into a water-insoluble condensation product and dyeing thefibres with the direct cotton dyestuff from an acid dyebath.

3. A process for dyeing nylon fibres at an enhanced rate of absorptionwith direct cotton dyestuffs having little aifinity for nylon whichcomprises treating the nylon fibres with an aqueous solution containingformaldehyde and cyanamide, converting the formaldehyde and cyanamideinto a water-insoluble condensation product and dyeing the fibres withthe direct cotton dyestuff from an acid dyebath.

4. A process for dyeing nylon fibres at an enhanced rate of absorptionwith direct cotton dyestuns having little ailinity for nylon whichcomprises treating the nylon fibres with an aqueous solution containingformaldehyde and diphenylguanidine, converting the formaldehyde anddiphenylguanidine into a water-insoluble condensation product and dyeingthe fibres with the direct cotton dyestuff from an acid dyebath.

5. A process for dyeing nylon fibres at an enhanced rate of absorptionwith direct cotton dyestufis having little afiinity for nylon whichcomprises treating the nylon fibres with an aqueous solution containingformaldehyde and guanidine adipate, converting the formaldehyde andguanidine adipate into a water-insoluble condensation product and dyeingthe fibres with the direct cotton dyestufi from an acid dyebath.

JAMES HUTCHISON MACGREGOR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS OTHER REFERENCES Stott, Dyeing of Nylon Fibres,"article in ,American Dyestuff Reporter for Oct. 2, 1939,

pages P582-P584.

Certificate of Correction Patent No. 2,458,397. January 4, 1949.

JAMES HUTOHISON MACGREGOR It is hereby certified that errors appear inthe printed specification of the above numbered patent requiringcorrection as follows:

Column 3, line 3, before the Word temperature insert room; line 26,strike out yard and insert instead the yam; and that the said LettersPatent should be read with these corrections therein that the samemay-conform to the record of the case in the Patent Office.

Signed and sealed this 31st day of May, A. D. 1949.

- THOMAS F. MURPHY,

Assistwnt commissioner of Patents.

